Ring back tones are individual audio files that take the place of the standard tones a caller hears while waiting for the phone to be answered. The possibility for users to increase the personalization of their communication experience makes ring back tones an attractive service.
The customized ring back tone is a very popular and attractive service to mobile users and wireless service providers. The mobile subscriber who purchases this service can choose whether or not a selected tone, melody, commercial message, or special sound, instead of the traditional audio ring tone, is provided to a particular caller from the time of the call setup to when the mobile terminal answers, or until “no page response” or “no answer” is detected by the system.
The choice of customized ring back tone service including selected tone, melody, commercial message, or specific sound is pre-selected on a calling party number basis through the Internet or calling a number that can reach the customized ring back tone system. For wireless service providers there are a number of approaches to provide customized ring back tone service to the caller for customized ring back tone mobile terminals based on their network configuration. In one such approach, a customized ring back tone server is connected to the caller where the call is terminated to a mobile switching center where the mobile terminal is currently located in a service area of the mobile switching center.
With this approach a call is terminated in a mobile switching center where the mobile subscriber record exists, the mobile switching center checking the called mobile terminal profile in its home location register/visitor location register record. If the called mobile terminal has customized ring back tone service active, then the serving mobile switching center connects the caller to the customized ring back tone server while it pages the called mobile terminal so that the caller hears the pre-selected customized ring back tone treatment instead of normal audible ringing tone. Hence, a decision regarding whether or not the mobile switching center connects the customized ring back tone server to the caller is based on the called mobile terminal profile in the home location register/visitor location register record, which indicates whether or not this mobile terminal has customized ring back tone service.
However, when an incoming call from a public switched telephone network to a mobile terminal arrives at a serving mobile switching center, and when the home location register determines that the call should be routed locally, the serving mobile switching center connects the caller to the customized ring back tone server while the serving mobile switching center pages the mobile terminal locally. The called mobile terminal may not respond to the local paging because it is moving into a bordering mobile service center serving area. The called mobile terminal may respond to the paging from a bordering mobile switching center, which returns a temporary local directory number to the serving mobile switching center in an Intersystem Page Return Result operation. The serving mobile switching center then delivers this call to the bordering mobile switching center via the allocated temporary local directory number while the caller is connected to the customized ring back tone server. When the bordering mobile switching center receives the call terminated to the local temporary local directory number, it connects the caller to the customized ring back tone server again based on the called mobile terminal profile. Therefore, when serving mobile switching center and the bordering mobile switching center both connect the caller to the customized ring back tone server, the caller may hear a non-coherent customer ring back tone treatment, and network resource use for customized ring back tone service is increased for that call.
Thus, it is a drawback of the prior art that there does not exist a method and apparatus that permits only one serving mobile switching center to connect an incoming call from a communication terminal to a customized ring back tone server when a called mobile terminal moves from an area of a serving mobile switching center to an area of a bordering mobile switching center.